In electronics and electrical engineering fuses, short for ‘fusible link’, are used to protect a device and wire-harnesses against an excess current. Typically, the fuse has a metal wire or strip which connects the fuse contacts, The wire or strip melts when too much current flows. When the metal strip melts, the electrical connection between the fuse contacts breaks, and hence the fuse breaks the circuit of which the fuse is a part. Thereby, the device is protected from an excessive current.
However, a general disadvantage of a fuse is that it cannot be integrated in an integrated circuit. Furthermore, when the connection is broken the fuse has to be replaced with a new fuse, which is particularly cumbersome in case the fuse is in a position that cannot be accessed easily, as is typically the case in automotive vehicles, such as cars.
Unites States Patent Application Publication US 2005/0135037 describes an electronic fuse comprising an integrated circuit having a control output terminal coupled to a control electrode of a power semiconductor switching device. The power semiconductor switching device is coupled in series with a load between first and second potentials. The integrated circuit further comprises a current sense input for sensing the current through the power semiconductor switching device, and a driver circuit for driving the power semi-conductor switching device, which is coupled to a current limiting circuit responsive to the sensed current in the power semiconductor switching device. The current limiting circuit controls the driver circuit such that if the current through the power semiconductor switching device exceeds a predetermined threshold, the current limiting circuit generates a command to pulse the power semiconductor switching device on and off in a period of pulsed operation to maintain the average current in the power semiconductor switching device below a predetermined level. The electronic fuse further comprises a first timer circuit for limiting the period of pulsed operation to a pre-programmed first duration and further for controlling the power semiconductor switching device whereby the power semiconductor switching device is turned off when two commands to pulse the power semiconductor switching device are generated by the current limiting circuit within a duration less than a predetermined second duration.
However, a disadvantage of the electronic fuse disclosed in the above identified US patent application Publication is that the behavior thereof does not correspond to the behavior of a conventional fuse. Furthermore, the pulsing on and off modifies the current. Furthermore, the electronic fuse known from this prior art document consumes a relatively high amount of power because switching the current on and off requires a high amount of energy.